ccgwebmaster, I think, I'm approaching the problem from a different angle. The resource which is available at no cost and en mass are machines. What we don't have are developers. So, I simply look which language do most devs speak. The probability to get some one with JS skills involved is a hell of lot higher than someone who can code shaders on a GPU. And it is much easier to make a running program fast than a fast one running.
Mozilla launched asm.js, google that. They use a special semantic to tell the compiler about types and achieve already 50% with the first implementation, but as said, I wouldn't care about speed now.
Obviously the needed resources are not available here in this forum. Who might be addressed as sponsor? Google Summer of Code comes to my mind. Might be enough to get a very little pilot, let's say version 0.00001 where others can connect later.
Btw. the Navier Stokes code I've linked is part of Google Chrome's test suite. There might be already some one working on a similar project.
Yes, the BBC projects introduces ensembles, that's why each client runs his own (really) simple model. Don't think this approach allows to include ice sheet models or runs on smart phones.
May be you have heard of Internet Census 2012: http://internetcensus2012.bitbucket.org/paper.html
One Person did the whole thing, build a plattform, the database and the clients. He scanned the complete Internet, every single IP address, multiple times, by using an interesting distributed approach. Basically he hijacked hundreds of thousands routers and other devices, uploaded silently his own code and let them scan a subnet and report the results.
The project was completely illegal, but he has programmed kind of agents, clever enough to adapt to the machine they run on and to copy itself to other clients - if available - with a subtask to fulfill and to report up stream. Essentially a self replicating avalanche. Very smart.